3 Answers
3

While brace expansion like {1,2} originates in csh in the late 70s, and found its way to Bourne-like shells in ksh in the late 80s, the {n1..n2} variant came a lot later first in zsh in 1995 (2.6-beta4).

bash copied it in 2004 (3.0) and ksh93 in 2005 (ksh93r).

Probably the shell you're trying this in is neither of those or is an older version of bash and ksh93.

@user43312: why are you still using RH9? It has been unmaintained for many many years. AS Stephane wrote it is a feature of recent bash versions. So it's very unlikely that your bash version supports it. You can check the version using bash --version. And just to be sure check if you are running a bash shell by checking the $SHELL variable or simply running ps. To use this feature you might try to start a zsh shell (zsh) first. Anothher workaround would be to use something like "mkdir $(seq 1 10)".
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BramSep 29 '13 at 11:10

1

@polemon The startup behaviour of another shell (ie. which files it sources upon startup), not mimicry of another shell.
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Chris DownSep 29 '13 at 14:36